wm

I have similar problem in a tiled pool with Zodiac Indigo, which has the 'new' brushes probably the same shape  and substance  as you have.  I am sure the problem is the substance of the brushes. The robot is pressing against the wall, but the brush is too elastic what results in a kind of swinging  <--> movement at the wall. If I lift it gently, it starts climbing. I asked at many pool shops (zodiac do not answers) and they recomended me now in Germany the PVA white brushes (both for 30 EUR ) instead of the original ones BESP and the older black PVC brushes. I am waiting these days to have it delivered and to test it.